twistedtree
Guru
Sounds like both you and Easting are going to proceed with your original plans. It would be great to hear back from you how it works out once you have some time using it.
DC vs AC Generator
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Sounds like both you and Easting are going to proceed with your original plans. It would be great to hear back from you how it works out once you have some time using it.
I can charge at about 175 honest amps with my single cylinder diesel gen with alternator. It's about as simple as it gets. Honestly did not really follow the complexity talked about here at all, having built and used one for a few years. I use it typically to put back roughly 200-300 ah into the 1200ah bank in bulk. About the only thing that gets regulated is using a multi stage regulator. I pretty much never touch the throttle. When the Amps fall below 50, I shut it off usually.
The biggest con is that it is actually not that quiet. It took a bit of basic engineering skills to put together and large large cables that do not tolerate poor connections. Also, it's manual start and stop. I developed an arduino controller to auto start, but have failed to move it beyond the breadboard and actually finish soldering it up. For most folks, I'd recommend a typical automatic ac generator. The D.C. Gen is for the geeks. I'm actually adding a northern lights next month and will use that more often, though the D.C. Gen will charge faster than my ac charger.
The biggest con is that it is actually not that quiet. It took a bit of basic engineering skills to put together and large large cables that do not tolerate poor connections. Also, it's manual start and stop. I developed an arduino controller to auto start, but have failed to move it beyond the breadboard and actually finish soldering it up. For most folks, I'd recommend a typical automatic ac generator. The D.C. Gen is for the geeks. I'm actually adding a northern lights next month and will use that more often, though the D.C. Gen will charge faster than my ac charger.
ksanders
Moderator Emeritus
I just like the flexability of the AC generator.
We have a 9KW nice quiet Northern Lights generator. For battery charging we have a 150 amp charger that is intregal to the 3KW inverter.
When we start the generator in the morning when on the hook The batteries start charging. In bulk charge mode we run about 120 amps DC into our 800 amp hour bank.
We put on a pot of coffee on the stove during that time.
The hot water heater runs making sure we have hot water for a morning shower.
If I feel like it I'll run the watermaker for an hour or so, producing a days potable water.
Perhaps I'll do a load of laundry.
After breakfast the batteries are charged, the showers are done, and the laundry is ready for folding. We can then turn off the generator until time to make dinner.
Yes, it's hard to beat the flexability of a AC generator.
When we had our trailer boat we did the same thing, the only real differences were no watermaker or laundry, and a nifty reliable, quiet honda generator that we paid less than a grand for.
We have a 9KW nice quiet Northern Lights generator. For battery charging we have a 150 amp charger that is intregal to the 3KW inverter.
When we start the generator in the morning when on the hook The batteries start charging. In bulk charge mode we run about 120 amps DC into our 800 amp hour bank.
We put on a pot of coffee on the stove during that time.
The hot water heater runs making sure we have hot water for a morning shower.
If I feel like it I'll run the watermaker for an hour or so, producing a days potable water.
Perhaps I'll do a load of laundry.
After breakfast the batteries are charged, the showers are done, and the laundry is ready for folding. We can then turn off the generator until time to make dinner.
Yes, it's hard to beat the flexability of a AC generator.
When we had our trailer boat we did the same thing, the only real differences were no watermaker or laundry, and a nifty reliable, quiet honda generator that we paid less than a grand for.
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sunchaser
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Kevin
Your logical and simple approach is one shared by thousands of recreational boaters including me. But for those without a laundry, inverter, electric galley or water maker the question is how to best charge batteries for a 12 volt only system. Kinda like what was done half or more a century ago.
My first big power boat escapades were on a 36' vessel that had oil lamps and sterno cans for cooking. For many new trailer boats used today, Kenyon alcohol stoves and 12 volt systems work quite well. Camping on the water as practiced by tens of thousands of happy inland boaters
Your logical and simple approach is one shared by thousands of recreational boaters including me. But for those without a laundry, inverter, electric galley or water maker the question is how to best charge batteries for a 12 volt only system. Kinda like what was done half or more a century ago.
My first big power boat escapades were on a 36' vessel that had oil lamps and sterno cans for cooking. For many new trailer boats used today, Kenyon alcohol stoves and 12 volt systems work quite well. Camping on the water as practiced by tens of thousands of happy inland boaters
ksanders
Moderator Emeritus
Kevin
Your logical and simple approach is one shared by thousands of recreational boaters including me. But for those without a laundry, inverter, electric galley or water maker the question is how to best charge batteries for a 12 volt only system. Kinda like what was done half or more a century ago.
My first big power boat escapades were on a 36' vessel that had oil lamps and sterno cans for cooking. For many new trailer boats used today, Kenyon alcohol stoves and 12 volt systems work quite well. Camping on the water as practiced by tens of thousands of happy inland boaters
If I had a say mid 30 foot boat with minimal loads except battery charging I'd buy a small 1800 RPM diesel generator and a inverter/charger with capability to quickly charge my house bank. I know Northern Lights makes a 5KW unit and I think others do as well.
If my house bank was not large enough to support a charging load to approx 50% of the generators capacity, or if space or budget were a concern, I'd just go with a Honda portable. I know they are well engineered and reliable.
I would shy away from the 12 volt generators on the market, but thats just me. My concern is that the sales numbers of these units are pretty low. That means to me that there is not allot of money for extensive engineering, and that there are not enough units in the field to make for a well debugged system.
I could be way off base there, but if it was my money I'd be very hesitant. Especially when there are other solutions (like a $1000 Honda generator) that I can 100% guarantee will work great.
There are several people here on TF that seem to have the technical skills to engineer a basic single speed 12 volt generator on their own. Engineering the throttle circuit to properly adjust the rpm would be a tad more challenging. Thats an OK idea and one I seriously considered on a previous boat. Then I went to the store, and bought a Honda generator, and spent my free time fishing.
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FF
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why not run a belt driven air conditioning compressor?
This is very complex,
But using a large engine driven compressor to freeze a quantity of eutetic fluid does work, mostly for sail folks who only want to operate the engine every 3-4 days , and have ice cream aboard.
This too is complex , and not cheap, but what price silence?
This is very complex,
But using a large engine driven compressor to freeze a quantity of eutetic fluid does work, mostly for sail folks who only want to operate the engine every 3-4 days , and have ice cream aboard.
This too is complex , and not cheap, but what price silence?
sdowney717
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I have an Onan generator 6500 watts AC output.
I have heard from smokstak.com the DC side on MCCK can put out 25 amps.
I have a belt driven raw and fresh water pump. I could potentially mount a high output DC alternator on another dedicated pulley. But why bother, the main engines each have 80 amp alternators, so I suppose can run them up in neutral and get 150 amps DC output.
I actually did that one day when the gen shut down and had to cook using the inverter. It did work, allowed us to finish cooking.
I have heard from smokstak.com the DC side on MCCK can put out 25 amps.
I have a belt driven raw and fresh water pump. I could potentially mount a high output DC alternator on another dedicated pulley. But why bother, the main engines each have 80 amp alternators, so I suppose can run them up in neutral and get 150 amps DC output.
I actually did that one day when the gen shut down and had to cook using the inverter. It did work, allowed us to finish cooking.
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johnrupp
Senior Member
Victron Energy had a free downloadable e book on this subject. It is called Energy Unlimited. It is a wealth of knowledge and ideas for the techies among us.
The book covers the pros and cons of alternative sources of energy compared to having a large AC generator. Large alternator on engine, DC generator, smaller AC generator with inverter etc.
It available on their website.
The book covers the pros and cons of alternative sources of energy compared to having a large AC generator. Large alternator on engine, DC generator, smaller AC generator with inverter etc.
It available on their website.
twistedtree
Guru
I think you nailed the real reason why people build or buy DC generators. It's a geek thing, and I say that comfortably because I proudly count myself as a geek. This is why, despite all the good reasoning in this and other threads explaining by it's not such a great idea, the people who have posed the questions are going to do it anyway. They want to experiment, they want to tinker, and they want to build things, and they want to do things differently.
My only suggestion would be to think about where you want to apply your geekness. Is it in creating or integrating a DC generator into your boat's electrical system? Or would it be better applied to optimizing your main engine charging system? Or maybe optimizing your AC generator utilization? Or maybe adding auto-start to your generator, or maybe adding solar? Or maybe build a hybrid power system where a small generator most of the time, and inverters provide the peak loading rather than oversizing the generator? Or would it be automating everything so as you get close to your boat, the heat turns up, the lights come one, the doors unlock, and the music comes on? There are lots of cool projects that are possible. And if a DC generator is the one that rings your bell, heck, go for it. Just let us know how it turns out.
North Baltic sea
Guru
To enable the appropriate quality AC power must first make a DC current and this is converted back to AC to power inverter. Thus obtain a pure sine wave curve, which is suitable for more sensitive electronics.
Fascinating conversation. Just wanted to add, that whenever talking about the super quiet Honda generators (i.e.1000is-3000is) is good to take into consideration that whatever one chooses for their applications, take into consideration the power range of the generator 'as long it stays in ecomode', meaning in the 48db-53db range, such whisper mode is what has given them their 'super quiet' reputation. Example a 2000is (43 lbs) is 49db noise level (normal conversation is about ~64db by way of reference) at 1000W draw, but up to 58db noise 'out of ecomode' meaning 2x as loud.. A 3000is is 134 pounds, more a permanent location type, will not come out of quiet 48db noise range meaning doesn't come out of ecomode till about 1800w, why many people upgrade to it, if mobility is not coveted or necessary. The 3000is also has electric start, remote start AND can be easily converted to run on propane, though some ingenious types have brought those options also to the smaller 1000is and 2000is.
I am new to this industry, but had every sort of RV over 40 years, and there we go to achieve this: what type of power can we have that one could run a true quite generator (48db-53db noise level) and run an AC simultaneously? There is the goal. My existing Northern Light generator in the boat I just bought, running at noise factors in the 60's will not do, since it is really akin to having someone talking in your ear constantly, so now I am presently experimenting with how to shield the NL's noise; there are many ways (see how outboard industries do it using special materials in their cowles via combinations of absorption and reflection) and see how that works. Necessity (quietness in this case) is the mother of invention.
I am new to this industry, but had every sort of RV over 40 years, and there we go to achieve this: what type of power can we have that one could run a true quite generator (48db-53db noise level) and run an AC simultaneously? There is the goal. My existing Northern Light generator in the boat I just bought, running at noise factors in the 60's will not do, since it is really akin to having someone talking in your ear constantly, so now I am presently experimenting with how to shield the NL's noise; there are many ways (see how outboard industries do it using special materials in their cowles via combinations of absorption and reflection) and see how that works. Necessity (quietness in this case) is the mother of invention.
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Mearns wrote: "what type of power can we have that one could run a true quite generator (48db-53db noise level) and run an AC simultaneously?"
Well, it will take a lot, and the Honda 3000 won't do it. Better to work on a sound enclosure for your NL genset, maybe buy one from NL, than to think about a portable generator in Eco mode.
A 16,000 btu A/C which is typical on most boats, uses 15 amps which is 1,800 watts. Any additional load like the battery charger, water heater, etc will put you out of Eco mode for the Honda 3000. And I would much, much rather run my NL generator than a Honda up on deck.
David
Well, it will take a lot, and the Honda 3000 won't do it. Better to work on a sound enclosure for your NL genset, maybe buy one from NL, than to think about a portable generator in Eco mode.
A 16,000 btu A/C which is typical on most boats, uses 15 amps which is 1,800 watts. Any additional load like the battery charger, water heater, etc will put you out of Eco mode for the Honda 3000. And I would much, much rather run my NL generator than a Honda up on deck.
David
Ski in NC
Technical Guru
If a NL gennie is too noisy, there may be an issue with the installation. Even without a sound box, if installed in an engine room, in the cabin it should be just a "purr" audible.
Some older units have no silencing on the air intake, that can be fixed with some creative engineering or an upfit with newer parts.
Some older units have no silencing on the air intake, that can be fixed with some creative engineering or an upfit with newer parts.
Thankfully a 16kw AC is not an absolutely must in my case, a 12kw will do because of size of boat, and the Honda 3000is does adjust accordingly because of its excellent auto-rpm adjuster, meaning unlike the 2000is is not a strict, bi-modily 100% in or out of 'eco mode'.
Yesterday spend 5 hrs with a mechanic going over every engine, specially the Northern Lite and yes achieved marked progress in noise reduction, now playing with noise absorbing and reflecting panels, and other ideas. Even with its very mounts. Getting close, and looks like my 3000is made not have to be pressed into service after all.
The noise battle is indeed a constant with engines in close quarters with humans.
Yesterday spend 5 hrs with a mechanic going over every engine, specially the Northern Lite and yes achieved marked progress in noise reduction, now playing with noise absorbing and reflecting panels, and other ideas. Even with its very mounts. Getting close, and looks like my 3000is made not have to be pressed into service after all.
The noise battle is indeed a constant with engines in close quarters with humans.
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Lepke
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Foam like styrofoam blocks sound really well especially if the generator base is sitting on a 2"+ thick pad. I found much of the sound can be transmitted through the vessel structure unless it's completely isolated. But it's a fire hazard. Lights easily and produces toxic fumes.
We put better hard rubber motor mounts, major help and you are right is the reverberation that was 1/2 the battle. Also attaching the same material as used in outboard cowles (hood covers) and attaching it under the engine room floor panels, another major reduction. Almost to 'purr' level. If goes no further I am thrilled with the NL now. It has 2485 hrs, and I 'think' is the original; I suppose that is not a lot of hours, considering it is 37 years old!
FF
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If Honda noise is a hassle trail it 50 ft back in your dink.
Here is link to the entire boat, which includes engine pictures. I did remove intake cover and expected a foam in it of some type, as customary in many generators, but there is none. I trust that is normal.
prairie 29 trawler for sale - Guatemala Yacht Broker - Rio Dulce
prairie 29 trawler for sale - Guatemala Yacht Broker - Rio Dulce
